Colombato L A, Albillos A, Groszmann R J
Hepatic Hemodynamic Laboratory, Veterans Administration Medical Center, New Haven, Connecticut, USA.
Gastroenterology. 1996 Jan;110(1):193-8. doi: 10.1053/gast.1996.v110.pm8536856.
BACKGROUND & AIMS: In portal hypertension, peripheral vasodilatation (PVD) causes Na+ retention as a result of vascular underfilling. The central blood volume is responsible for the vascular filling signals to baroreceptors and volume receptors. The aim of this study was to determine the role of central blood volume in Na+ retention in portal hypertensive rats.
Mean arterial pressure, portal pressure, cardiac output, total peripheral resistance, central blood volume, and extracellular Na+ space were assessed daily in rats after portal vein ligation or sham operation until a hyperdynamic circulatory state developed.
On day 1, portal vein-ligated rats had PVD and a diminished central blood volume (1.26 +/- 0.04 vs. 1.47 +/- 0.09 mL/100 g body wt; P < 0.05). On day 2, Na+ space increased in portal vein-ligated rats (38.1 +/- 0.5 vs. 33.1 +/- 0.5 mL/100 g body wt; P < 0.01). From day 2 on, normalization of central blood volume and cessation of Na+ retention were observed despite persistent PVD. On day 4, portal vein-ligated rats developed a hyperdynamic circulatory state with a normal central blood volume and persistent PVD.
Although total peripheral resistance remains decreased, Na+ retention ceases after central blood volume is normalized. Central blood volume therefore appears to be the signal for Na+ retention. Although PVD persists after Na+ retention ceases, it may contribute to Na+ retention by decreasing central blood volume.
在门静脉高压症中，外周血管扩张（PVD）由于血管充盈不足导致钠潴留。中心血容量负责向压力感受器和容量感受器传递血管充盈信号。本研究的目的是确定中心血容量在门静脉高压大鼠钠潴留中的作用。
在门静脉结扎或假手术后，每天评估大鼠的平均动脉压、门静脉压、心输出量、总外周阻力、中心血容量和细胞外钠空间，直至出现高动力循环状态。
第1天，门静脉结扎大鼠出现外周血管扩张且中心血容量减少（1.26±0.04 vs. 1.47±0.09 mL/100 g体重；P<0.05）。第2天，门静脉结扎大鼠的钠空间增加（38.1±0.5 vs. 33.1±0.5 mL/100 g体重；P<0.01）。从第2天开始，尽管外周血管扩张持续存在，但中心血容量恢复正常且钠潴留停止。第4天，门静脉结扎大鼠出现高动力循环状态，中心血容量正常但外周血管扩张持续存在。
尽管总外周阻力持续降低，但中心血容量恢复正常后钠潴留停止。因此，中心血容量似乎是钠潴留的信号。尽管钠潴留停止后外周血管扩张仍持续存在，但它可能通过降低中心血容量导致钠潴留。
